Controller for electric motors.



l] Nv ITED STATES PATENT OFFICE.

WILLIAM D. POMEROY, OE NORWOOD, OHIO', AssIGNOR, RY MEsNE ASSIGN- MENTS, To TIIE BULLOCK ELECTRIC COMPANY, A CORPORATION OE OHIO..

CONTROLLER FOR ELECTRIC MOTORS..

Specification of Letters Patent.

Patented June 4, 1907'.`

Application filed December 1, 1903. Renewed November 26. 1906. Serial No. 345,177.

T au whom, it may concern:

Be it known that I, WILLIAM D. POMEROY,

a citizen of the United States, residing at y.rious machine tools or other driven mechan- .ste

mined interval of time is caused to fore this resistance is cutout, such interval 'of time being of sufiicient duration to allow the motor to speed up to some extent. Upon cutting out the resistance a further increase .means for lessening the strain upon the motor upon change of speed and to produce a gradual change in speed in passing from one to the next. y my invention a multiple voltage system is used, and I provide automatic means for controlling the msertion and cutting out of armature resistance. Upon each increase in potential at the terminals of the motor, resistanceis inserted Iin the armature circuit so that the full increase in potential is not at .once applied to the armature.

ance is4 afterward automatically removed This resistfrom the armature circuit and a predetere apse bein speed occurs which brings the armature to thejspeed of the next running step.

, Further features of my invention will be disclosed in the following speciiication and accom anying drawing, and the novelty thereoi) will be definitely set forth in the appended claims.

The drawing shows a diagram of my invention.

Generators for'the multiple voltage system are indicated at 1, 1 in series with each other and connected by the switch 2 to the three wire mains 3, A3', 3 and supplying voltages .which diii'er from each other; f or'example generator A1 may give 160 volts between mains 3 and 3', and generator l may give 90 volts between mains 3 and 3". The armature of the motor whose speed is to be varied is .indicated at 4 and its field winding at 5 oon- K nected in series with the variable iield resistance 6. The field winding with its resistance is connected across the mains 3, 3 by the leads 7, 8 and so receives the -full voltage of both generators. In series with the armature lead 9 is the resistance 9a. Leads to the terminals of switch 10 form a short circuit about the armature resistance when said switch is closed. This switch is provided with an upwardly extending soft-"iron arni 1l, which forms the core of the coil 12. Alower extension from the switch carries the plunger 13 which works in the cylinder 14, forming a dash-pot. The plunger 13 is provided with openings 15 and carnes a loosely fitting flat rin 16 which normally closes the openings 15. The cylinder 14 is provided with openings 1'7 located equally distant from the closed bottom Oi' the cylinder. Vhen current passes in coil 12, the switch is raised with a comparatively slow movement as. the air passes to the bottom of the plunger only by leakage about the same. Just before the switch is closed, however, the lun er passes by the holes 17, permitting a iree ow of air below it and the switch then closes with a sudden movement. When no current passes in coil 12, the switch quickly falls, due either to the force of gravity, or Spring pressure against the movable part, as preferred, the air from beneath the plunger passing freely through the holes 15 as the ring 16 is then raised from'its seat.

The parts above described are interconnected and also connected to the ingers la, 1b, l, 1o of the controller as shown. The controller cylinder is made up of three metal drums 18, 19 and 20 insulated from each other. The two upper drums control the connections to the armature and have the contacts indicated held upon lugs projecting from the body of the drum. The lower cylinder Changes the field resistance and is in the form of a cylinder having cut-away portions.

VAs the cylinder is revolved from orn position IOO 3b, For position 2a follows: from main 3 21, drum 19, contact 22, mature 4, lead 24, switch 10 or resistance 9a according as said switch 10 is closed or open, leads 9 and 25, finger 1b, contact 26, drum 18, contact 27, finger 1d to main 3, thus subjecting the armature of the motor to the voltage of generator 1. For position 2a, the field connections are from main 3, field 5, finger 1, druin 20, finger 11', lead 8 to main 3, thus subjecting the field to the full voltage of mains 3, 3 with all of resistance 6 cut out. i

. 3i forbackward rotation of the motor. the path of the current is as to finger 1, contact Connection 1s also made from niain 3 through coil 12 to finger 1i and drum 20, which is connected to main 3 through finger 1J', and lead 8. The coil 12 is therefore subjected to the voltage of generator 1 and switch 10 is caused to close.

In tracing the circuits below, the switch 10 will be considered to be closed, as such is its ultimate position. Should the switch be open the current will flow through the resistance 9a instead of through said switch.

For position2", finger 1", is cut out of contact with drum 20, and a section of resistance 6 is inserted in the field circuit, the field current passing from-the field winding 5 to finger 1n through a.section of the field resistance and then to drum 20. No other changes take place, and by thus weakening the field of the-motor an increased speed is obtained. In the same way for position 2c a still further weakening of the field takes place by inserting another section of resistance 6 in the field circuit, and in this position current passes from the field 5 through two sections of resistance to finger 1m and druin 20.

For position 2d the armature connections are from main 3 to finger 1, contact 28, drum 19, contact 29, finger 1f, lead 23, arinature4, lead 24, switch 10, leads 9 and 25, finger 1b, contact 30,. drum 18, contact 31, finger 1, to main 3. The armature of the inotor is therefore subjected to the voltage of generator 1 which is greater than that of generator 1. The field connections and those of coil 12 are the same for this position as for position 2, and the speed of the motor is increased by the increase in voltage ap lied to its armature. For positions 2e an 2f the only changes that take place are the weakening of the field by cutting in sections of resistance 6, as in positions 2b and 2C.

For position 2g the armature connections are from main 3" to finger 1, contact 32, drum 19, contact 33, finger 1f, lead 23, armature 4, lead 24, switch 10, leads 9 and 25, finger 1b, contact 34, drum-18, contact 35, finger 1a to main 3. The armature of the motor is therefore subjectedA to the total voltage of The field connections and bothgenerators. n those of coil 12 are the same as .for positions 2a and 2d, with resistance 6 cut out, and infinger 1f, lead 23, ar-

through lead'7,l

l creased speed is obtained by the increase in electrornotive force applied to the motor armature.

For positions 2", 2, 25, 2k, and 2 the connections remain the same except that sections of resistance 6 are successively cut in sively weakening the field for increases in speed from positions 2g to 2l.

It will be noted that in passing from position 2c to 2d, and from 2f to 2g, at which times the change in voltage applied to the motor armature takes place, finger 1i-is ,momentarily cut out of contact with the drum 20 and circuit through coil 12 is broken. At the instant finger 1 breaks contact with drum 20, switch 10 drops and resistance 9a is inserted in lseries with the armature 4, so that when the increased voltage is applied to the armature, this resistance will prevent a too sudden rush of current with consequent strains on the motor. As coil 12 is again placed in circuit at positions 2d and 2g, the switch 10 will be closed and the resistance 9a short. circuited, but on account of the slow upward movement of the switch the motor will have had sufficient time to increase in speed before the switch is closed. 'When the controller is moved from the off position to the starting position 2, the switch 10 is closed in the saine slow manner.

gers are in positions 3aL to 3i successively. For position 3a the current passes from main 3" to finger 1, contact 36, drum 19, contact 37, finger 1g, lead 9, switch 10, lead 24, armature 4, leads 23 and 38, finger 1c, contact 39, drum 18, contact 40, finger 1d., to main 3. The armature 4 is therefore subjected to voltage of generator 1, and the armature currentis reversed, while the field is the same as for position 2a. The direction of l rotation of the motor is therefore reversed and the motor operates at its slowest speed. l

For positions 3b and 3C the field strength is weakened as before.l AFor-position 3d the circuit is as follows: main 3', finger 1e, contact 41, drum 19, contact 42, finger 1g, lead 9, switch 10, lead 24, armature 4, leads 23 and 38, finger 1c, contact 43, drum 18, contact 44, finger 1a to main 3. For this position, although the motor has its full field strength as in position 3, an increased speed is obtained by reason of the armature being subjected to the voltage of generator 1. At positions 3e and 3f, increased speeds are obtained by weakening the field strength. For position 3g, the connections are as follows: Frommain to finger 1h, contact 45, drum 19, contact l 46, finger 1g, lead 9,switch 10, lead 24, armature 4, leads 23 and 38, finger 1, contact 47, drum 18, contact 48, finger 1a to main 3, the

motor in this case being subjected to the total voltage of both generators. At positions 3h and 3i the field strength is weakened. in

until it is all in circuit, in this manner succes- For reverse rotation of the motor, the fini IOC passing from positions 30 to 3d and from 3f to 3g, the armature resistance 9a is cut in to relieve the strain on the motor, as already explained with reference to passing from positions 2 to 2d and from 2f to 2g. It is therefore evident from the above description that twelve speeds forward and nine speeds in the reverse direction are obtained.

Although I have described a specific embodiment of my invention, it is evident that various modifications may be made therein without departing from the vscope of the claims.

I claim as my invention:

1. The combination of a multiple voltage system, a motor having an armature resistance, a shunt about said resistance, an electro-magnetically operated switch in said shunt, a controller and connecting leads, said controller having contacts adapted to vary the voltage applied to the armature circuit and to control said electro-magnetically operated switch.

2. .The combination of a multiple voltage system, a motor having an armature resistance, a shunt about said resistance, a switch in said shunt which normally tends to open, electro-magnetic means for closing said switch, a controller and connecting leads, said controller having contacts adapted to vary the voltage applied to the armature circuit and to open and close the circuit of said electro-magnetic means upon changing the voltage of the armature circuit.

3. The combination of a multiple voltage system, a motor having armature resistance, a shunt about said resistance, a switch in said shunt which normally tends to open, electromagnetic means for closing said switch,

means for retarding the closing of said switch, a controller and connecting leads, said controller having contacts adapted to vary the voltage applied to the armature circuit and to open and close the circuit of said electroma netic means upon changing the voltage of t e armature circuit.

4. The combination of a multiple voltage system, a motor arranged to be variably connected to`said system, a resistance for the motor armature circuit, a shunt about said resistance, and a remotely controlled switch in said shunt.

5. The combination of a multiple-voltage system, a motor arranged to be connected across diierent sets of the mains of the system, a resistance in the motor armature circuit, an electromagnetically operated switch in shunt to said resistance, and a controller for said switch.

6. The combination of a multiple-voltage system, a motor arranged to be connected across different sets of the mains of the system, resistance in the motor armature circu1t, a switch in shunt to said resistance, and

a master controller for said switch from which said switch is separate.

7. The combination of a multiple-voltage system, a motor, a controller arranged to connect the armature of said motor across different sets of the mains of the system, a resistance in the circuit of said armature, and a switch separate from said controller but controlled thereby and in shunt to said resistance.

8. The combination of a multiple-voltage system, a motor, a controller arranged to connect the armature of -said motor across different sets of the mains of the system, a resistance in the circuit of'said armature, and a switch separate from said controller but controlled thereby and in shunt to said resistance.

9. In a switch Afor dynamo-electric machinery, the combination with a motor, a circuit therefor, and resistance for the circuit, of means for eii'ecting changes in the potential on the leads of the armature circuit of the motor, and means remote from the aforesaid means for cutting said resistance into and out of said circuit.

10. In a switch for dynamo-electric machinery, the combination with a motor, iield and armature circuits therefonof a controller' for ei'lecting an increase in potential of the armature circuit, and an automatic time device remote from the controller for delaying the increase in potential at the armature terminals.

11. In a switch for dynamo-electric machinery, the combination with a motor, field and armatureA circuits therefor, and resistance for the armature circuit, of a controller for varying the potential on the leads of the armature circuit, and a switch away from said controller for cutting said resistance into said armature circuit for a predetermined time whenever the controller varies said potential.

12. In a switch for dynamo-electric machinery, the combination with a motor, field and armature circuits therefor, and resistance for the armaturel circuit, of a controller for varying the potential on the leads of the armature circuit, and an electromagnetically operated switch for cutting said resistance too IIO

into said armature circuit for a predetermined time whenever said potential is varied. In testimony whereof I affix my signature, in presence of two wltnesses.

WILLIAM D. POMEROY. 

